Switch



April 28, 1925. 1,535,807

' L. F. BLUME SWITCH Fil d Jan. 13, 1925 2 Sheets-Sheet 1 n llll u Inventor": Louis F. Blurne,

April 28, 1925. 1,535,807

L. F. BLUME SWITCH Filed Jan. 13. 19215 2 Sheets-Shet 2 Inventor-. Louis F. Blume,

WMJQQZ His Attorney.

Patented Apr. 28, 1925.

UNITED STATES PATENT OFFICE.

LOUIS F. BLUME. F PITTSFIELD, MASSACHUSETTS, ASSIGNQR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

SWITCH.

Application flied January 13, 1923.

To all whom it may concern: 7 7

Be it known that 1, Louis F. BLIIME, a citizen of the Unit-ed States, residing at Pittstield, county of Berkshire. State of 6 Massachusetts, have invented certain new and useful Improvements in Switches. of which the following is a specification.

My invention relates to switches The main object of the invention is to PXOVKlQHI] improved switch of compact construction adapted to complete a variety of desired con nections between a number of electrical conductors. A switch of this character 18 useful for varying tap connections from a transformer winding so as to obtain a desired voltage ratio between the trans former windings, compactness being desirable so that the switch may be located in the same casing with the transformer where the available 29 space is limited. A further object of the invention is to provide an improved switch which may be enclosed in the same casing with a transformer and conveniently operated by means extending through the eas- 5 ing so as to be easily accessible at some outside point. Other objects and advantages will appear.

The invention will be, described in connection with the accompanying drawings in which Fig. 1 is a longitudinal sectional view of one embodiment of the invention: Fig. 2 is a cross section on the line of Fig. 1; i Fig. 3 is a view similar to Fig. 2 but on a reduced scale and showing the movable parts of the switch in a different position; Fig. 4 is a diagrammatic view indicating how the switch may be connected to vary the etl'ec ,g'tlVB number of turns in a transformer winding; Fig. 5 is a longitudinal view, partly in section, of another embodiment of the in vention; and Fig. 6 is a sectional view on lflhe line. 66 of Fig. 5.

In the form of switch shown in Figs. 1. to 4 inclusive, a plurality of spaced conducting rods or terminals 1, 2, 3, a, 5, 6 and 7 are supported by a pair of insulating end lates 8 and 9. Seven such rods or terminals are shown but this particular number is not necessary and it will be apparent that a larger or smaller number ma be used if desired. These terminals surround a central shaft 10 carried bearings in the end plates 8 and 9. A binding morn her or connector 11 is rotatably supported about an offset portion of the shaft 10 and Serial No. 612,452.

serves to complete desired connections between the terminals 1 to 7. The connector 11 is divided longitudinally into two sections which are pressed yieldingly toward each other and about the offset portion of shaft 10 by bolts 12 with springs under their I heads. The connector 11 is retained in place on the shaft 10 by washers 13 and 14 and a cotter pin 15 on the shaft at each side of the connector. Figs. 1, 2 and 4 show the connector 11 as connecting the two terminals 1 and 4. It will be noted that in this position, the axis of the connector 11 is tan nt to the path of the offset portion of the s aft 10, this path being indicated by the circular broken line 16 in Figs. 2 and The springs on the bolts 12 press the two section of the connector 11 tightly against the terminals so as to assure good contact therewith.

The switch is operated by rotating the shaft 10, the two ends of the connector 11 being shifted alternately from one terminal to another. Starting with the connector 11 in the position indicated in Figs. 1, 2 and 4, clockwise. rotation of the shaft 10 at first moves the right-hand end of the connector 11 further onto the terminal 4 and its lefthand end off the terminal 1. The right-hand end of the connector 11 must remain in engagement with the terminal 4 but as soon as its left-hand end leaves the terminal 1 it is free to follow a path determined by the circular movement of the offset portion of the shaft 10. The position of the connector just after leaving the terminal 1 is indicated.

in Fig. As t'he shaft 10 is further rotated, the left hand end of the connector 11 will continue to describe a curved path which is convex toward the shaft 10 and the terminal 4 until finally this left-hand end of the connector 11 will move onto the terminal 7, the axis of the connector 11 then being again tangent to the path 16 of the offset portion of the shaft 10. A connection is now established through the switch between the terminals 4 and 7.

Each step in the operation of the switch is similar to the one 111st described. For instance, a still further clockwise rotation of the shaft 10 will at first move the left-hand end of the connector 11 further onto the terminal 7 and its right-hand end off the terminal 4. The right-hand end of the connector 1.1 will then move in a curved ath which is convex toward the shaft 10 an the terminal 7, the connector finally reaching another position tangent to the path Hi of the oliset portion of the shaft .10 and with its ri ht-hand end on the terminal 3. This. estab ishes a connection through the switch between the com'iectors T and :5.

The diflerent terminal connecting positions of the connector 11 are shown by broken lines in Fig. 4 which indicates dia grammatically how the switch may be used to chan e tap connections from a transformer win ing in order to vary the ratio of transformation. The transformer has two windings 17 and 18, the winding 18 being formed in two main sections from which tap leads are connected to the terminals of the switch. The position of the switch connector shown in Fig. 4 is such that the two inside end tap leads are connected through the switch so that the entire winding is in circuit. It is obvious that by operating the switch as has been already described, small tap sections will be cut out of circuit alternatel from the two main sections of the winding 18 and thus the efl'ective number of turns in the winding 18 will be reduced. By operating the switch in the opposite or counter-clockwise direction, the small tap sections of the transformer winding will he cutback into circuit alternately in the two main transformer winding sections and thus the effective number of turns in the wind ing 18 will be increased. Stops l9 and 2) are provided at the terminals 1 and 5 it spectively so that the connector ll cannot pass beyond the limiting positions in which either all the tap sections of the transformer Winding 18 are connected in series or all these tap sections are cut out of circuit.

The pressure due to the spring bolts 12 between the contact surfaces of the ternii nals and the two sections of the connector 11 increases the capacity of the switch and is therefore desirable during such time as the switch is carrying current. 'hilc the position of the connector ll is being changed. however. it is ot' advantage to eliminate or reduce this pressure and the friction which it causes between the con act surfaces. ()ne of the objects. of he invention is to provide a structure which -li2lll possess these 'idvantag thus .31. pro ect ing from each cction c-l the connector ll rest against the prriplicrics (it the washers 18 which arc keyed to he shatt lil. ()ppo sitely diSPlH-(l dcpiw i ns r grooves in the peripheries of these "\Viltdlfli'r .22 are so located as to be directly under the ins :21 \Vlltll the connector it is in any one of its terminal t' llilltctlllg powc ns. This is shown learly in Fig. .5.

The depressions are just dccp enough to permit the spring bolts 12 to draw the contact surfaces of the connector 11 tightly ag inst opposite sid of the terminals. As toe shaft it) is to tated to shift one rid of the connector from one terminal to another the washers 13 are iotuici'l. with the shaft but the connector is kept tiom rotating with the shaft and washers. by the, terminals with which it is in cngagcnu-nt. There is thus relative r0ta tion bctwcn the connector and the shaft and washers and this moves the depressions in the washers out from under the pins 21, forcing the pins and the two sections of the connector apart slightly as indicated in Fig. 3. The friction between the connector and terminalsfis eliminated or reduced so that the connector may move easily to its new position. Just as the connector reaches another terminal connecting position, the depressions in the washers 13 again reach the pins ll and the spring bolts 12 again draw the connector sections tightly against the terminals.

A modification of the invention is shown in Figs. 5 and 6. This form of switch includes a plurality of spaced conducting rods or terminals :22, 23", 24, 25, 26 and 97 supported between a pair of insulating plates 12b and surrounding a central shaft 29 calricd in hearings in the plates 28. In Fig. 5. the terminal 24 is removed and parts are shown in section to reveal structur Six terminals uniformly spaced about the shaft '15) are vshown. although it will be apparent that a larger or smaller number may be used it glcsirvd. Desired connections between the terminals are made by a connector 30 rotnlably supported about an offset port. in of thc shaft 2.) and'opcrable in a manner imilar to the manner in which the connector 11 of Figs. 1 to l is operated. The connec- [or 30, howcvcr, has its contact surfaces Ill all at one side of the operating shaft so as to connect adjacent terminals at one side of the switch instead ol terminals disposed at opposite sides thereof. The contact surl'aci-s I l are resilientlv supported by spring arms 32 projecting from the bodyof the connector So. The connector 30 is provided Wlll! ii pair of rigid arms 33 with anti-frie lion rollers 34 at their outer ends. A pair oi" rings 35 secured to the end plates 28 have radial grooves adapted to receive the rollers Ill to coopcrute with the shaft .39 in shifting the connector tit) between its ditl'erent termi- [Lil minim-ting positions. A roller 34 and ciooved ring l?) are shown at each end oi the connector Il but one of these rollers with its rin may ohviowdy be omitted if so dc- =zrcd.

lhc conne tor in this form of switch is hifted from tlllt' position to another in a manner similar to that in which thcconncctor of the switch shown in l ig's. l to 4 is shil'lcd. ln the position shown in Figs. 5 and ti. the connector is connecting the two lii'llllllIll-. 3:2 rind i i. To shift the conncc' in 7.11 sh. po ition in which connection is made between the terminals 23 and 24, the shaft 29 is rotated in a clockwise direct-ion. During the first part of this rotation of the shaft 29, the contact surfaces 31 are in engagement with and are held between the terminals 22 and 23 so that the connector is forced to rotate in a counter-clockwise direction, the rollers 34 approaching the radial grooves opposite the terminal Further rotation of the shaft 29 moves the rollers into these grooves and withdraws the contact surfaces from between the terminals 22 and 23. The engagement of the rollers with these grooves now forces the connector to continue to rotate in a counter-clockwise direction and the contact surfaces 31 to approach the space between the terminals 23 and 24. Finally the contact surfaces 31 are moved into this space and forced by a toggle action firmly into contact with the terminals 23 and 24:, the rollers 34 being withdrawn from the grooves and moved into a position midway between the grooves opposite the terminals 26 and 27. This operation may be repeated to shift the connector to its next terminal connecting position between the terminals 24 and 25. It is obvious that by rotating the shaft 29 in the opposite or counter-clockwise direction, the connector will be shifted in a clockwise direction opposite tothat just described; for instance, from the terminals 22 and 23 to the terminals 27 and 22.

What I claim as new and desire to secure by Letters Patent of the United States, is,

1. A switch including a plurality of terminals, a terminal connecting member having surfaces for contact with said terminals, and means for supporting said connecting member and for moving it to carry one of its contact surfaces from one terminal to another in a curved path convex toward said supporting means and in a direction along said path opposite to that of said supporting means.

2. A switch including a plurality of ten minals, a rotatable shaft, a terminal connecting member rotatably carried by said shaft and having surfaces for contact with said terminals, the portion of the shaft carrying said connecting member being offset, whereby a contact surface of said connecting member may be withdrawn from a terminal by rotation of the shaft, and means for guiding said connector to direct said contact surface from one terminal to another during rotation of the shaft.

3. A switch including a plurality of terminals, a rotatable shaft having an offset portion, a terminal connecting member ro tatably carried by the offset portion of said shaft and having a surface for contact with a terminal, and means for causing said connecting member to rotate during rotation of the shaft to transfer said contact surface from one terminal to another in a direction around the shaft opposite to that of the shaft.

4. A switch including a plurality of terminals, a rotatable shaft having an offset portion, a terminal connecting member rotatably carried by the offset portion of said shaft and having a surface for contact with a terminal, and means for guiding said contact surface from one terminal to another during rotation of the shaft and in a direction around the shaft opposite to that of the shaft.

5. A switch including a plurality of terminals, a terminal connecting member having opposed contact surfaces, means for pressing said surfaces against opposite sides of a terminal, means for transferring said contact surfaces from one terminal to another, and means for separating said surfaces to reduce friction with the terminals during transfer.

In witness whereof, I have hereunto set my hand this 10th day of Jan. 1923.

LOUIS F. BLUME. 

